There isn't an Android phone out that compares to the iPhone X. All of Android's offerings are a few steps behind. The snapdragon 835 chip is a few generations behind the a11 bionic chip currently powering the new iPhone offerings. Actually the last year chip also beats the pants off the 835 chip in day to day usage.
The OnePlus is a phone that doesn't even deserve to get mentioned. There's nothing wrong with a 1080p screen, but their low quality cameras, horrible phone os and secruity updating record and private data mining backdoor practices are horrible.
Xiaomi is fine. I've owned a cheap model from back in 2015. Phone has never had a problem. It doesn't matter if you get the cheapest or the most expensive model. The cameras on those phones are all terrible. Even the newest mi mix 2 has a horrible camera. I'm comparing it to the 2015 Nexus 6p.
Google's Pixel phones. I could recommend either last year's version or the smaller pixel 2(2017) version. The 2 xl (2017) is plagued with problems. It seems as if each week since it's release, there have been massive screen, Bluetooth, audio, os issues. Stay away.
I hate to say it, but apple is the way to go. They also have a worldwide warranty. You can't beat it.
Sony is probably the best Android phone maker out right now when it comes to support and timely updates for their phones. They just really need to update the design and the camera software. Hopefully 2018 will be their year.